maui-linux/Xamarin.Forms.Platform.UAP/PickerRenderer.cs

216 строки
6.0 KiB
C#

using System;
using System.ComponentModel;
using System.Threading.Tasks;
using Windows.UI.Core;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media;
using Xamarin.Forms.Internals;
namespace Xamarin.Forms.Platform.UWP
{
public class PickerRenderer : ViewRenderer<Picker, FormsComboBox>
{
bool _fontApplied;
bool _isAnimating;
Brush _defaultBrush;
FontFamily _defaultFontFamily;
protected override void Dispose(bool disposing)
{
if (disposing)
{
if (Control != null)
{
_isAnimating = false;
Control.SelectionChanged -= OnControlSelectionChanged;
Control.DropDownOpened -= OnDropDownOpenStateChanged;
Control.DropDownClosed -= OnDropDownOpenStateChanged;
Control.OpenAnimationCompleted -= ControlOnOpenAnimationCompleted;
Control.Loaded -= ControlOnLoaded;
}
}
base.Dispose(disposing);
}
protected override void OnElementChanged(ElementChangedEventArgs<Picker> e)
{
if (e.NewElement != null)
{
if (Control == null)
{
SetNativeControl(new FormsComboBox());
Control.SelectionChanged += OnControlSelectionChanged;
Control.DropDownOpened += OnDropDownOpenStateChanged;
Control.DropDownClosed += OnDropDownOpenStateChanged;
Control.OpenAnimationCompleted += ControlOnOpenAnimationCompleted;
Control.ClosedAnimationStarted += ControlOnClosedAnimationStarted;
Control.Loaded += ControlOnLoaded;
}
else
{
WireUpFormsVsm();
}
Control.ItemsSource = ((LockableObservableListWrapper)Element.Items)._list;
UpdateTitle();
UpdateSelectedIndex();
}
base.OnElementChanged(e);
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (e.PropertyName == Picker.SelectedIndexProperty.PropertyName)
UpdateSelectedIndex();
else if (e.PropertyName == Picker.TitleProperty.PropertyName)
UpdateTitle();
else if (e.PropertyName == Picker.TextColorProperty.PropertyName)
UpdateTextColor();
else if (e.PropertyName == Picker.FontAttributesProperty.PropertyName || e.PropertyName == Picker.FontFamilyProperty.PropertyName || e.PropertyName == Picker.FontSizeProperty.PropertyName)
UpdateFont();
}
void ControlOnLoaded(object sender, RoutedEventArgs routedEventArgs)
{
WireUpFormsVsm();
// The defaults from the control template won't be available
// right away; we have to wait until after the template has been applied
_defaultBrush = Control.Foreground;
_defaultFontFamily = Control.FontFamily;
UpdateFont();
UpdateTextColor();
}
void WireUpFormsVsm()
{
if (Element.UseFormsVsm())
{
InterceptVisualStateManager.Hook(Control.GetFirstDescendant<Windows.UI.Xaml.Controls.Grid>(), Control, Element);
}
}
void ControlOnClosedAnimationStarted(object sender, EventArgs eventArgs)
{
if (!Control.IsFullScreen)
{
// Start refreshing while the control's closing animation runs;
// OnDropDownOpenStateChanged will take care of stopping the refresh
StartAnimationRefresh();
}
}
void ControlOnOpenAnimationCompleted(object sender, EventArgs eventArgs)
{
_isAnimating = false;
if (!Control.IsFullScreen)
{
// Force a final redraw after the closing animation has completed
((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
}
}
void OnControlSelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (Element != null)
Element.SelectedIndex = Control.SelectedIndex;
}
void OnDropDownOpenStateChanged(object sender, object o)
{
if (Control.IsDropDownOpen)
{
if (Control.IsOpeningAnimated && !Control.IsFullScreen)
{
// Start running the animation refresh;
// ControlOnOpenAnimationCompleted will take care of stopping it
StartAnimationRefresh();
}
else
{
((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
}
}
else
{
// The ComboBox is now closed; if we were animating the closure, stop
_isAnimating = false;
// and force the final redraw
((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
}
}
/// <summary>
/// Forces redraw of the control during opening/closing animations to provide
/// a smoother sliding animation for the surrounding controls
/// Only applies on the phone and only when there are fewer than 6 items in the picker
/// </summary>
void StartAnimationRefresh()
{
_isAnimating = true;
Task.Factory.StartNew(async () =>
{
while (_isAnimating)
{
await Task.Delay(16);
await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => ((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged));
}
});
}
void UpdateFont()
{
if (Control == null)
return;
Picker picker = Element;
if (picker == null)
return;
bool pickerIsDefault = picker.FontFamily == null && picker.FontSize == Device.GetNamedSize(NamedSize.Default, typeof(Picker), true) && picker.FontAttributes == FontAttributes.None;
if (pickerIsDefault && !_fontApplied)
return;
if (pickerIsDefault)
{
// ReSharper disable AccessToStaticMemberViaDerivedType
Control.ClearValue(ComboBox.FontStyleProperty);
Control.ClearValue(ComboBox.FontSizeProperty);
Control.ClearValue(ComboBox.FontFamilyProperty);
Control.ClearValue(ComboBox.FontWeightProperty);
Control.ClearValue(ComboBox.FontStretchProperty);
// ReSharper restore AccessToStaticMemberViaDerivedType
}
else
{
Control.ApplyFont(picker);
}
_fontApplied = true;
}
void UpdateSelectedIndex()
{
Control.SelectedIndex = Element.SelectedIndex;
}
void UpdateTextColor()
{
Color color = Element.TextColor;
Control.Foreground = color.IsDefault ? (_defaultBrush ?? color.ToBrush()) : color.ToBrush();
}
void UpdateTitle()
{
Control.Header = Element.Title;
}
}
}